Hermetic sealing with high-speed transmission for hard disk drive

ABSTRACT

Embodiments disclosed herein generally relate to hermetic electrical connectors used in hard disk drives. The hermetic electrical connector includes a barrier structure having a first plurality of connecting pads disposed on a first surface of the barrier structure and a second plurality of connecting pads disposed on a second surface of the barrier structure opposite the first surface. A plurality of conductors is disposed within the barrier structure, and each conductor is coupled to a connecting pad of the first plurality of connecting pads and a corresponding connecting pad of the second plurality of connecting pads. The barrier structure further includes a dielectric material between the first and second surfaces, and one or more layers embedded in the dielectric material. The addition of the layers helps choke the helium gas flow, thus improving sealing of the electrical connector while maintaining high-speed electrical transmission.

BACKGROUND

Field

Embodiments disclosed herein generally relate to electrical connectorsfor electronic devices, and more particularly to hermetic electricalconnectors used in hard disk drives.

Description of the Related Art

A hard disk drive (HDD) is a non-volatile storage device that is housedin a protective enclosure and stores digitally encoded data on one ormore magnetic media, such as magnetic disks. When an HDD is inoperation, each magnetic disk is rapidly rotated by a spindle system.Data is read from and written to the magnetic disk using a read/writehead that is positioned over a specific location of the magnetic disk byan actuator.

A read/write head uses a magnetic field to read data from and write datato the surface of the magnetic disk. Write heads make use of theelectricity flowing through a coil, which produces a magnetic field.Electrical pulses are sent to the write head, with different patterns ofpositive and negative currents. The current in the coil of the writehead induces a magnetic field across the gap between the head and themagnetic disk, which in turn magnetizes a small area on the recordingdisk.

There are various benefits to operating an HDD in helium ambient,because the density of helium gas is one seventh that of air. Forexample, operating an HDD in helium reduces the drag force acting on thespinning disk stack and the mechanical power used by the disk spindlemotor. Further, operating in helium gas reduces flutter of the disks andthe suspension, allowing for disks to be placed closer together andincreasing the areal density by enabling a smaller, narrower data trackpitch. The lower shear forces and more efficient thermal conduction ofhelium also mean the HDD will run cooler and will emit less acousticnoise. The reliability of the HDD is also increased due to low humidity,less sensitivity to altitude and external pressure variations, and theabsence of corrosive gases or contaminants. However, known devices andmethods for sealing an HDD in helium result in a marked increase in thecost of the HDD, and high-speed electrical transmission may besacrificed in order to improve sealing of the HDD with respect to heliumgas.

Therefore, there is a need in the art for an improved apparatus forsealing an HDD with helium gas inside.

SUMMARY

Embodiments disclosed herein generally relate to hermetic electricalconnectors used in hard disk drives. The hermetic electrical connectorincludes a barrier structure having a first plurality of connecting padsdisposed on a first surface of the barrier structure and a secondplurality of connecting pads disposed on a second surface of the barrierstructure opposite the first surface. A plurality of conductors isdisposed within the barrier structure, and each conductor is coupled toa connecting pad of the first plurality of connecting pads and acorresponding connecting pad of the second plurality of connecting pads.The barrier structure further includes a dielectric material between thefirst and second surfaces, and one or more layers embedded in thedielectric material. The addition of the layers helps choke the heliumgas flow, thus improving sealing of the electrical connector whilemaintaining high-speed electrical transmission.

In one embodiment, a hermetic electrical connector includes an externalconnector, an internal connector, and a barrier structure disposedbetween the external connector and the internal connector. The barrierstructure includes a dielectric material (having a first surface and asecond surface opposite the first surface) and one or more layersembedded in the dielectric material. The one or more layers eachincludes a plurality of openings. The barrier structure further includesa plurality of conductors embedded in the dielectric material. Eachconductor extends through a corresponding opening of the plurality ofopenings of each layer.

In another embodiment, a hermetic electrical connector includes anexternal connector, an internal connector, and a barrier structuredisposed between the external connector and the internal connector. Thebarrier structure includes a dielectric material having a first surfaceand a second surface opposite the first surface, a first plurality ofconnecting pads disposed on the first surface, a second plurality ofconnecting pads disposed on the second surface, and a plurality ofconductors embedded in the dielectric material. Each conductor has afirst end adjacent a corresponding connecting pad of the first pluralityof connecting pads and a second end adjacent a corresponding connectingpad of the second plurality of connecting pads. The barrier structurefurther includes a first ground layer embedded in the dielectricmaterial, and the first ground layer is coplanar with the first end ofeach conductor. The barrier structure further includes a second groundlayer embedded in the dielectric material, and the second ground layeris coplanar with the second end of each conductor. The barrier structurefurther includes one or more layers embedded in the dielectric material,and the one or more layers are located between the first and secondground layers.

In another embodiment, a hard disk drive (HDD) includes one or moremagnetic media, one or more sliders, one or more magnetic headassemblies, and a hermetic electrical connector. The hermetic electricalconnector includes an external connector, an internal connector, and abarrier structure disposed between the external connector and theinternal connector. The barrier structure includes a dielectric material(having a first surface and a second surface opposite the first surface)and one or more layers embedded in the dielectric material. The one ormore layers each includes a plurality of openings. The barrier structurefurther includes a plurality of conductors embedded in the dielectricmaterial. Each conductor extends through a corresponding opening of theplurality of openings of each layer.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the disclosurecan be understood in detail, a more particular description of thedisclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments in any field involving magnetic sensors.

FIGS. 1A and 1B schematically illustrate an HDD according to embodimentsdescribed herein.

FIG. 2 is a perspective, cross-sectional view of a portion of the HDDaccording to embodiments described herein.

FIGS. 3A-3B are perspective, cross-sectional views of a barrierstructure according to embodiments described herein.

FIG. 4 is a perspective, cross-sectional view of the barrier structureaccording to embodiments described herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

In the following, reference is made to embodiments. However, it shouldbe understood that the disclosure is not limited to specific describedembodiments. Instead, any combination of the following features andelements, whether related to different embodiments or not, iscontemplated to implement and practice the claimed subject matter.Furthermore, although embodiments described herein may achieveadvantages over other possible solutions and/or over the prior art,whether or not a particular advantage is achieved by a given embodimentis not limiting of the claimed subject matter. Thus, the followingaspects, features, embodiments and advantages are merely illustrativeand are not considered elements or limitations of the appended claimsexcept where explicitly recited in a claim(s).

Embodiments disclosed herein generally relate to hermetic electricalconnectors used in hard disk drives (HDDs). The hermetic electricalconnector includes a barrier structure having a first plurality ofconnecting pads disposed on a first surface of the barrier structure anda second plurality of connecting pads disposed on a second surface ofthe barrier structure opposite the first surface. A plurality ofconductors is disposed within the barrier structure, and each conductoris coupled to a connecting pad of the first plurality of connecting padsand a corresponding connecting pad of the second plurality of connectingpads. The barrier structure further includes a dielectric materialbetween the first and second surfaces, and one or more layers embeddedin the dielectric material. The addition of the layers helps choke thehelium gas flow, thus improving sealing of the electrical connectorwhile maintaining high-speed electrical transmission.

FIG. 1A illustrates a schematic front view of an exemplary hard diskdrive (HDD) 100 according to an embodiment described herein. Asillustrated, HDD 100 may include one or more magnetic media 110, such asmagnetic disks, actuator means 120, actuator arms 130 associated witheach of the magnetic media, and spindle motor 140 affixed in a chassis150. The one or more magnetic media 110 may be arranged vertically asillustrated in FIG. 1A. Moreover, the one or more magnetic media may becoupled with the spindle motor 140.

One or more sliders 170 may be positioned near the magnetic media 110,each slider 170 supporting one or more magnetic head assemblies 180.Magnetic media 110 may include any suitable patterns of data tracks,such as annular patterns of concentric data tracks on both the top andbottom surfaces of each magnetic medium 110. As the magnetic mediumrotates, the slider 170 moves radially in and out over the top and/orbottom surface so that the magnetic head assembly 180 may accessdifferent tracks of the magnetic medium 110 where desired data arewritten. Each slider 170 is attached to an actuator arm 130 via asuspension arm (not shown). The actuator arm 130 may be configured toswivel around actuator axis 131 to place the magnetic head assemblies180 on a particular data track. The suspension arm provides a slightspring force which biases the slider 170 towards the magnetic media 110.Each actuator arm 130 is attached to the actuator means 120. Theactuator means 120 as shown in FIG. 1A may be a voice coil motor (VCM).The VCM comprises a coil movable within a fixed magnetic field, thedirection and speed of the coil movements being controlled by the motorcurrent signals supplied by a control unit (not shown).

During operation of the HDD 100, the rotation of the magnetic media 110generates an air bearing between each slider 170 and magnetic media 110which exerts an upward force or lift on the slider 170. The air bearingthus counter-balances the slight spring force of the suspension arm andsupports slider 170 off and slightly above the media 110 surface by asmall, substantially constant spacing during normal operation. The term“air” used herein may include any suitable gas. In one embodiment, theHDD 100 is filled with helium gas.

The HDD 100 may further include a hermetic electrical connector 160 thatis coupled to an arm-electronics module 164 via an interconnect cable162, as shown in FIG. 1A. The hermetic electrical connector 160 may beused to electrically connect the interior components of the HDD 100 withan electronic device, such as a computer.

The above description of a typical magnetic media storage system and theaccompanying illustration of FIG. 1A are for representative purposesonly. It should be apparent that media storage systems may contain alarge number of media and actuators, and each actuator may support anumber of sliders.

FIG. 1B is a schematic back view of the HDD 100 with a back cover 172according to an embodiment described herein. As shown in FIG. 1B, theHDD 100 may include the hermetic electrical connector 160, and thehermetic electrical connector 160 may include an external connector 166formed through the back cover 172. Again, the external connector 166 maybe used to electrically connect the HDD 100 with any suitable electronicdevice, such as a computer. The external connector 166 of the hermeticelectrical connector 160 may include a plurality of pins 168 forestablishing electrical connection with the electronic device. In oneembodiment, there are 28 pins, but it is to be understood that more orfewer pins may be present. In order to prevent gas, such as helium gas,from leaking out of the HDD 100, the hermetic electrical connector 160may hermetically seal the HDD 100 without sacrificing high-speedelectrical transmission.

FIG. 2 is a cross-sectional perspective view of a portion of the HDD 100according to embodiments described herein. As shown in FIG. 2, the HDD100 includes the hermetic electrical connector 160 coupled to a bracket206. In one embodiment, the bracket 206 is coupled to the chassis 150and is not part of the chassis 150. In another embodiment, the bracket206 is part of the chassis 150. The hermetic electrical connector 160may include the external connector 166 for electrically connecting withan electronic device, an internal connector 202 for electricallyconnecting with the internal components of the HDD 100, and a barrierstructure 204 disposed between the external connector 166 and theinternal connector 202. The barrier structure 204 may be disposed at thecenter (with respect to a thickness of the hermetic electrical connector160) of the hermetic electrical connector 160 and may be independent ofthe circuit layers in the internal connector 202 and the externalconnector 166. As a result, it is possible to suppress the influence ofthe capacitance of the hermetic electrical connector 160. In addition,the independent and centrally-located barrier structure 204 (withrespect to the hermetic electrical connector 160) also ensures theconsistency of the characteristic impedance, which ensures thehigh-speed electrical transmission through the hermetic electricalconnector 160.

FIGS. 3A-3B are cross-sectional perspective views of the barrierstructure 204 according to embodiments described herein. As shown inFIG. 3A, the barrier structure 204 includes a dielectric material 303having a first surface 304 and a second surface 308 opposite the firstsurface 304. The dielectric material may be any suitable dielectricmaterial, such as phenolic paper, epoxy paper, glass composite, glassepoxy, or polymer. The dielectric material 303 may be a multilayerstructure. A first plurality of connecting pads 302 may be disposed onthe first surface 304, and a second plurality of connecting pads 306 maybe disposed on the second surface 308. The first surface 304 may becoupled to the external connector 166 (FIG. 1B), and the first pluralityof connecting pads 302 may be electrically connected to the plurality ofpins 168 (FIG. 1B). Similarly, the second surface 308 may be coupled tothe internal connector 202, and the second plurality of connecting pads306 may be electrically connected to a plurality of pins (not shown)disposed on the internal connector 202.

The first plurality of connecting pads 302 and the second plurality ofconnecting pads 306 may be electrically connected by a plurality ofconductors 310, as shown in FIG. 3A. Each conductor 310 may include afirst end 312 adjacent a corresponding connecting pad 302 of the firstplurality of connecting pads 302, and the first end 312 may beelectrically connected to the corresponding connecting pad 302 by aconductor 316. Each conductor 310 may also include a second end 314adjacent a corresponding connecting pad 306 of the second plurality ofconnecting pads 306, and the second end 314 may be electricallyconnected to the corresponding connecting pad 306 by a conductor 318.The plurality of conductors 310 and the conductors 316, 318 may beembedded in the dielectric material 303 and may be made of anelectrically conductive material, such as copper, conductive polymer, ornickel. The first plurality of connecting pads 302 and the secondplurality of connecting pads 306 may be offset (i.e., not aligned).

The barrier structure 204 may also include ground layers 320, 322, asshown in FIG. 3A. The ground layers 320, 322 may be made of anelectrically conductive material, such as copper, conductive polymer, ornickel. In one embodiment, the ground layer 320 is level, or coplanar,with the first end 312 of the plurality of conductors 310, and theground layer 322 is level, or coplanar, with the second end 314 of theplurality of conductors 310. A distance D1 may be between the groundlayer 320 and the connecting pad 302, and a distance D2 may be betweenthe ground layer 322 and the connecting pad 306. The distances D1 and D2ensure that the connecting pad 302, 306 are not overlapping with theground layer 320, 322, respectively, in order to minimize parasiticcapacitance. To further minimize parasitic capacitance, the distances D1and/or D2 may be greater than a width of a signal line. Parasiticcapacitance is an unwanted capacitance that exists between parts of anelectronic component because of the parts' proximity to each other. Byincreasing the distance between the parts, such as between the ends 312,314 of the conductor 310 and the ground layers 320, 322, respectively,parasitic capacitance is reduced.

The dielectric material 303 may be porous with respective to smallmolecules (such as helium gas), so helium gas inside the HDD 100 maydiffuse or leak out of the dielectric material 303. One or more layers330 may be embedded in the dielectric material 303 in order to reducethe gradient of partial pressure even if the molecules are small. Thelayers 330 may be made of a metal or a material having a permeability ofabout under the 1.0e-14 g/cm*Torr so that small molecules such as heliumcannot diffuse through. The one or more layers 330 may be made ofaluminum, copper, ceramic, quartz, Vycor®, Pyrex® 7740 borosilicateglass, Corning 1720 aluminosilicate glass, neoprene, butyl rubber, ornitrile rubber (Buna-N). The one or more layers 330 may becentrally-located within the dielectric material 303. In other words,the distance between the layer 330 closest to the first surface 304 andthe first surface 304 may be the same as the distance between the layer330 closest to the second surface 308 and the second surface 308. In oneembodiment, there are two layers 330 disposed between the ground layers320, 322, as shown in FIG. 3A, but it is to be understood that more orfewer layers 330 may be present. In one embodiment, one layer 330 isutilized instead of two layers 330. The two layers 330 may be alignedand parallel. A plurality of openings 332 may be formed in each layer330, and each conductor 310 of the plurality of conductors 310 mayextend through openings 332 of the layers 330. A distance D3 may bebetween each layer 330 and each conductor 310. The distance D3 may besmaller than the distances D1 and D2. In one embodiment, the distance D3may be about 150 microns or more, such as about 200 microns or 500microns. The smaller distance D3 reduces the diffusion rate of heliumgas through the dielectric material 303 because helium gas cannotdiffuse through the one or more layers 330. However, the distance D3 isnot small enough to increase parasitic capacitance. The distance D3between the layer 330 and the conductor 310 is small enough to improveair tightness of the barrier structure 204 but large enough not toincrease parasitic capacitance.

FIG. 3B is a cross-sectional perspective view of the barrier structure204 according to another embodiment described herein. As shown in FIG.3B, the ground layers 320, 322 may be removed in order to further reduceparasitic capacitance. Portions of the dielectric material 303 may beexposed on the first surface 304, and the exposed portion may have awidth D4. The exposed portion may be between the plurality of connectingpads 302 and a metal pad 350 or between adjacent rows of connecting pads302. The distance D3, which is between each layer 330 and the conductor310, may be smaller than the width D4. In one embodiment, the distanceD3 is about 150 microns. In another embodiment, the distance D3 is about200 microns. Similarly, having a smaller distance D3 compared to D4helps choke the flow of helium gas in the dielectric material 303, whichdecreases leak rate. In one embodiment, the leak rate of the HDD 100including the hermetic electrical connector 160 having the barrierstructure 204 is about 50% less than that of an HDD having aconventional hermetic electrical connector.

FIG. 4 is a cross-sectional perspective view of the barrier structure204 according to embodiments described herein. In order to betterillustrate, the dielectric material 303 is omitted in FIG. 4. As shownin FIG. 4, each conductor 310 extends through the one or more layers330. The first end 312 of each conductor 310 is electrically connectedto a corresponding connecting pad 302 via the conductor 316. Eachconductor may include a cylindrical body having a cross-sectionaldiameter of about 300 microns. Each opening 332 in each layer 330 mayhave a diameter equal to the diameter of each conductor 310 plus twotimes the distance D3 (FIG. 3A). In one embodiment, the diameter of eachopening 332 is equal to the diameter of the conductor 310 plus 300microns. In another embodiment, the diameter of each opening 332 isequal to the diameter of the conductor 310 plus 400 microns. Theopenings 332 may be circular and the cylindrical body of each conductor310 may be centrally-located within each opening 332. In other words,each conductor 310 and the corresponding opening 332 may be concentric.Again, the only places helium gas can leak or diffuse through within thedielectric material 303 are the plurality of openings 332. Because ofthe relatively small distance between the conductor 310 located withinthe opening 332 and the layer 330, helium gas flow within the dielectricmaterial 303 is choked, leading to reduced helium gas leaking out of theHDD 100.

In summary, a hermetic electrical connector used in an HDD is disclosed.The hermetic electrical connector may include a barrier structure havinga dielectric material and one or more layers embedded in the dielectricmaterial. The one or more layers help prevent or reduce small molecules,such as helium gas, from diffusing or leaking through the dielectricmaterial. Additionally, a plurality of openings may be formed in eachlayer, and a conductor may extend through each opening. By having aspecific spacing between each conductor and the layer, parasiticcapacitance is reduced.

While the foregoing is directed to embodiments of the disclosure, otherand further embodiments may be devised without departing from the basicscope thereof, and the scope thereof is determined by the claims thatfollow.

What is claimed is:
 1. A hermetic electrical connector, comprising: anexternal connector; an internal connector; and a barrier structuredisposed between the external connector and the internal connector,wherein the barrier structure comprises: a dielectric material having afirst surface and a second surface opposite the first surface; one ormore layers embedded in the dielectric material, wherein the one or morelayers each includes a plurality of openings; and a plurality ofconductors embedded in the dielectric material, wherein each conductorextends through a corresponding opening of the plurality of openings ofeach layer.
 2. The hermetic electrical connector of claim 1, wherein thebarrier structure is centrally-located within the hermetic electricalconnector.
 3. The hermetic electrical connector of claim 1, wherein alayer of the one or more layers comprises aluminum, copper, ceramic,quartz, borosilicate glass, aluminosilicate glass, neoprene, butylrubber, or nitrile rubber (Buna-N).
 4. The hermetic electrical connectorof claim 1, wherein the one or more layers comprise two layers.
 5. Thehermetic electrical connector of claim 1, wherein the one or more layerscomprise one layer.
 6. The hermetic electrical connector of claim 1,wherein a conductor of the plurality of conductors is concentric with acorresponding opening of the plurality of openings, and the conductor isspaced apart from a layer of the one or more layers.
 7. The hermeticelectrical connector of claim 6, wherein the conductor is spaced apartfrom the layer by about at least 150 microns.
 8. The hermetic electricalconnector of claim 6, wherein the conductor is spaced apart from thelayer by about 150 microns to about 500 microns.
 9. The hermeticelectrical connector of claim 1, wherein an opening of the plurality ofopenings has a diameter of about at least 600 microns.
 10. The hermeticelectrical connector of claim 1, wherein an opening of the plurality ofopenings has a diameter equal to a diameter of a conductor of theplurality of conductors plus at least 300 microns.
 11. A hermeticelectrical connector, comprising: an external connector; an internalconnector; and a barrier structure disposed between the externalconnector and the internal connector, wherein the barrier structurecomprises: a dielectric material having a first surface and a secondsurface opposite the first surface; a first plurality of connecting padsdisposed on the first surface; a second plurality of connecting padsdisposed on the second surface; a plurality of conductors embedded inthe dielectric material, wherein each conductor has a first end adjacenta corresponding connecting pad of the first plurality of connecting padsand a second end adjacent a corresponding connecting pad of the secondplurality of connecting pads; a first ground layer embedded in thedielectric material, wherein the first ground layer is coplanar with thefirst end of each conductor; a second ground layer embedded in thedielectric material, wherein the second ground layer is coplanar withthe second end of each conductor; and one or more layers embedded in thedielectric material, wherein the one or more layers are located betweenthe first and second ground layers.
 12. The hermetic electricalconnector of claim 11, wherein a layer of the one or more layerscomprises aluminum, copper, ceramic, quartz, borosilicate glass,aluminosilicate glass, neoprene, butyl rubber, or nitrile rubber(Buna-N).
 13. The hermetic electrical connector of claim 11, wherein theone or more layers each includes a plurality of openings.
 14. Thehermetic electrical connector of claim 13, wherein a conductor of theplurality of conductors is concentric with a corresponding opening ofthe plurality of openings, and the conductor is spaced apart from alayer of the one or more layers.
 15. The hermetic electrical connectorof claim 14, wherein the conductor is spaced apart from the layer byabout at least 150 microns.
 16. The hermetic electrical connector ofclaim 14, wherein the conductor is spaced apart from the layer by about150 microns to about 500 microns.
 17. A hard disk drive, comprising: oneor more magnetic media; one or more sliders; one or more magnetic headassemblies; and a hermetic electrical connector, comprising: an externalconnector; an internal connector; and a barrier structure disposedbetween the external connector and the internal connector, wherein thebarrier structure comprises: a dielectric material having a firstsurface and a second surface opposite the first surface; one or morelayers embedded in the dielectric material, wherein the one or morelayers each includes a plurality of openings; and a plurality ofconductors embedded in the dielectric material, wherein each conductorextends through a corresponding opening of the plurality of openings ofeach layer.
 18. The hard disk drive of claim 17, wherein a layer of theone or more layers comprises aluminum, copper, ceramic, quartz,borosilicate glass, aluminosilicate glass, neoprene, butyl rubber, ornitrile rubber (Buna-N).
 19. The hard disk drive of claim 17, wherein anopening of the plurality of openings has a diameter equal to a diameterof a conductor of the plurality of conductors plus at least 300 microns.20. The hard disk drive of claim 17, wherein an opening of the pluralityof openings has a diameter equal to a diameter of a conductor of theplurality of conductors plus about 300 microns to about 1000 microns.